In manufacturing electronic devices, various processes are performed on a semiconductor wafer (hereinafter, simply referred to as “wafer”) as a target substrate. For example, when a film forming process is performed on a surface of a wafer, there is used a film forming system including a film forming apparatus for performing film formation, a transfer unit for loading/unloading a wafer into/from the film forming apparatus, and the like.
The transfer unit of the film forming system needs to accurately transfer the wafer to a preset mounting position (e.g., a mounting table to be described later) in the film forming apparatus. In this regard, Japanese Patent Application Publication No. 2008-306162, for example, discloses a technique for obtaining “positional deviation information” of a wafer supported by supporting arms based on an image of the wafer which is captured by a CCD (Charge-Coupled Device) camera having an imaging device and provided near an inlet of a processing unit capable of performing film formation or the like and then correcting a destination of the wafer by the supporting arms.
In the film forming apparatus, a non-film formation region (region where film formation is not performed) may be formed at an edge portion of the wafer in order to prevent an end effector of the transfer unit from being contaminated due to film formation on a backside of the wafer. In the case of forming the non-film formation region at the wafer, a film formation region is formed at an inner side of the non-film formation region.
However, a technique for forming the non-film formation region at the edge portion of the wafer is not disclosed in Japanese Patent Application Publication No. 2008-306162. Therefore, when the non-film formation region is formed at an incorrect position of the edge portion of the wafer, the positional deviation of the non-film formation region cannot be corrected regardless of the correction of the destination of the wafer based on the imaging result of the CCD camera.
In the film forming system, a multilayer film may be formed on the wafer by performing film formation by using a plurality of film forming apparatuses. In that case, if the non-film formation region is formed at an incorrect position in the respective film forming apparatuses, films having misaligned film forming positions are laminated. Accordingly, it is not possible to form a multilayer film having good characteristics.